In an interview with the CNN presenter Nina dos Santos on the ITV stage, Buhlmann said he didn’t believe it would be in the interest of the UK to pull itself out of the European Union, the largest trading block in the world.
He said: "Why wouldn’t you want to be the fastest growing economy in the largest trading block? Do you want to maintain a high level of influence? If you are outside the UK, the UK having influence on the EU makes us more important.
"If you get a little bit of sovereignty back – such as how many sprinkles you can put on your cappuccino or whatever the latest bit of regulation is – you lose a lot of influence for a little bit more sovereignty and I don’t think that’s worth it."
The title of the session was "winning in the digital economy" and Buhlmann said Dentsu Aegis Network’s approach to the challenge of the changing digital economy is to focus on culture.
He said: "The fundamental if you think about it is the nature of how business is changing, is the pace of change. If you have an organisation of 40,000 how do you move them fast?
"The only way you can move them rapidly is through culture. Create a culture that is relevant and current for that business opportunity. Culture and organisation are critical.
"It’s very important to have a vibrant and strong vision for the business. We have nine network brands but we have one vision that is overarching for the whole organisation."
Denstu Aegis Network’s organic growth was 12.2 per cent in Europe last year, which Buhlmann said gave the business momentum, allowing it to invest including through acquisitions.
Buhlmann said globally China and US were the priorities for acquisitions as they are the "largest economies" and account for "most of the media innovation" whereas in other markets the group is looking for "infill".
He continues: "We made acquisitions in Spain when it wasn’t very popular to do so. We don’t set down barriers – we give people permission to sponsor opportunities. Have long list of 60/70 targets."
Following the session Buhlmann spoke to Campaign about the threat of Brexit as well as the recent controversy around the WPP chief executive’s expected £70 million pay last year.
Buhlmann said: "That’s not an issue for me, it’s an issue for his shareholders and his stakeholders. If his shareholders and stakeholders are happy with that and he’s earned that he has the unique position of being a founder CEO and that’s not really an issue for me to comment on."